The present invention generally relates to rail track inspection equipment, and more specifically to equipment for automatically monitoring the condition of railroad rails.
US railroads are subject to several different track inspection processes. First, as dictated by the Federal Railroad Administration (FRA), the railroads are required to visually inspect the rail on a regular basis. The frequency of these visual inspections is determined by the speed at which the railroad wishes trains to travel on the specific rail in question, also known as the Class or Classification of the track. For Class 4 and 5 track, the railroad is required to traverse the rail (by foot or on a hy-rail vehicle) twice weekly, with at least one calendar day intervals between tests. As is known in the art, a hy-rail vehicle is a standard truck equipped for travel along railroad track, with a set of hydraulically operated rail-type wheels mounted to the front and rear of the vehicle.
In addition to visual track inspections required by the FRA, a frequent, periodic search for internal defects must be conducted for all rails in Classes 4 through 5 tracks. The practice of searching for internal flaws is known as rail flaw detection using Non Destructive Testing techniques such as Ultrasonic Testing.
Current standard practice for rail flaw detection utilizes a process that is referred to as stop/start testing (SST). A custom SST rail flaw detection vehicle outfitted with real time on screen displays travels along the track looking for rail defects. At least one on-board operator interprets the on screen results and determines when to stop and verify that a defect exists. Testing frequency along the track is typically scheduled by the railroad based on predetermined risk management guidelines. The railroads balance the cost of increased test frequency versus the reduction of service failures (an interruption in revenue service) and derailments. In practice, railroad test frequencies typically far exceed the requirements by the FRA. However, for railroads, the cost of purchasing, maintaining and staffing and/or subcontracting conventional customized rail flaw detection vehicles prevents their widespread use, and accordingly limits the coverage and/or frequency of track monitoring.
Another drawback of conventional SST testing is that the typical ultrasonic system installation onto a testing vehicle involves a complex collection of cable wiring, ultrasonic signal cables, water plumbing, pneumatic air lines, and hydraulic hose, all of which need to be run and managed throughout the testing vehicle. This integration is time consuming and problematic for field service.